A “biocular” is a lens assembly which permits a human observer to view a magnified image of a single image source with both eyes looking through a common optical aperture. Biocular eyepieces are commonly used to magnify the image of a miniature cathode ray tube (CRT), image intensifiers, and flat panel micro-display image sources. Biocular lenses are widely used in head-up and head-down displays for both modern military and commercial aircraft, flight simulators, microscopes for semiconductor device inspection, and medical applications. The chief advantage of using a biocular eyepiece, as compared to a monocular eyepiece or a binocular eyepiece, is that the observer is able to freely move his head and use both eyes to see essentially the same image at the same light level on the same optical system. Typically, bioculars operate with image source format sizes on the order of 35 to 52 mm. In order to accommodate the standard range of human interpupillary distances from 55 to 72 mm, a biocular lens will typically have a front aperture diameter of about 60-80 mm. The apparent horizontal field of view is typically on the order of 36° or so. Because of the fact that each eye is viewing the image from a different vantage point, the correction of spherical aberration, longitudinal chromatic aberration, and sphero-chromatism within the biocular lens is necessary to avoid the experience of image “swimming” when the viewer is moving his eyes. The longitudinal chromatic aberration and sphero-chromatism must be corrected or otherwise eye strain will occur. These problems have resulted in relatively complex conventional biocular eye pieces. In many prior art cases, the optical aberrations prevented making the front aperture much larger than the interpupillary distance, which in turn imposes limitations that the left and right eyes individually cannot see the entire image, and only through fusion in the human brain can a complete field of vision be comprehended. Classical biocular eyepieces such as those disclosed in U.S. Pat. Nos. 3,922,072 and 4,183,624 require at least five to six refractive optical elements and generally have an overall length about twice that of the effective focal length.